(PARTIALLY SOLVED ) OpenGL stencil in 2D - need some help with implementation

Vaclav_

Addendum The "black" torroid solved! glEnable( GL_LIGHTING ); kills the display turns on "black light !!" Now working on actual stencil rendering... I am trying to implement 2D graph - Smith chart - using stencil buffer. I understand the stencil concept, but I am having issues with implementation. I found some examples, but all of them are way to complicated for my purpose. Here is my current (code) attempt , I culled from tutorial. It is very dated , so chances of discussion are nill. For test purposes I am trying to draw "torroid" and "cirle (outline)" to show only the "matching" parts. Since the "torroid" is draw in black I can see it overriding x,y coordinates lines / cross I have in my window. I sure would like somebody to help me with the actual rendering the stencil, but at present I cannot figure out HOW to change the "stencil" color from black. BTW the red circle is always draw in full - no stencil. This is "work in progress code" so pay no attention to comments or commented out code.

void OpenGL_CodeProject(void)
{
// enable depth and stencil buffers
glutInitDisplayMode(
GLUT_RGBA | GLUT_ALPHA | GLUT_DOUBLE | GLUT_DEPTH | GLUT_STENCIL);
// Push the GL attribute bits so that we don't wreck any settings
glPushAttrib( GL_ALL_ATTRIB_BITS );
glEnable( GL_LIGHTING ); kills the display
// Set the clear value for the stencil buffer, then clear it
glClearStencil(0);
glClear( GL_STENCIL_BUFFER_BIT );
glEnable( GL_STENCIL_TEST );
// glStencilMask is initially enable - where (?)
glStencilMask (0xFFFFFFFFFF); // added - has no effect
// Set the stencil buffer to write a 1 in every time
// a pixel is written to the screen
glStencilFunc( GL_ALWAYS, 1, 0xFFFF );
glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
// Render the object in black - where is "black" set ? defuult ??
// glPolygonMode( GL_FRONT_AND_BACK, GL_FILL );
// glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE); // do allow change colors in ANY (??) buffer
glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); // allow change colors in ANY buffer

// draw green torroid

// glColor3f( 0.0f, 1.0f, 0.0f ); // original code - has no effect
// RenderMesh3(); original code
// glutSolidCube(1);
// glutWireCube(10);

GLfloat x, y, angle;
//glClear( GL\_COLOR\_BUFFER\_BIT);
glColor3f(1.0, 0.0, 0.0);       no effect    
// window size in pixels / points
GLint m\_viewport\[4\];

glGetIntegerv( GL\_VIEWPORT, m\_viewport);
printf(" m\_viewport